Centrifugal drive for electric razor

ABSTRACT

DISCLOSED HEREIN IS AN ELECTRIC SHAVER HAVING A SHAVING HEAD COMPRISING AN OUTER OR FEMALE MEMBER HAVING A POLYGONAL BORE DEFINING AN INTERNAL BEARING SURFACE, A NUMBER OF SEGMENTS DEFINING CUTTING ELEMENTS ADJUSTABLY MOUNTED ON THE OUTER MEMBER SYMMETRICALLY WITH RESPECT TO THE BORE, AN INNER OR MALE MEMBER SUPPORTED ON THE OUTER MEMBER AND HAVING A PERIPHERAL POLYGONAL BEARING SURFACE POSITIONED WITHIN SAID BORE AND A CUTTING EDGE POSITIONED TO OPERATIVELY ENGAGE THE CUTTING ELEMENTS OF THE SEGMENTS, AN ELECTRIC MOTOR AND A VARIABLE RADIUS ECCENTRIC DRIVE ASSEMBLY OPERATIVELY CONNECTED TO THE MOTOR AND TO THE INNER MEMBER TO PROVIDE A POLYGONAL TRACING MOVEMENT OF THE INNER MEMBER RELATIVE TO THE OUTER MEMBER. A SHARPENING DEVICE IS ALSO INCLUDED AND IS ADAPTED TO BE MOUNTED ON THE INNER MEMBER TO SHARPEN THE SEGMENTS OR ON THE SEGMENTS TO SHARPEN THE INNER MEMBER.

oct- 12, 1971 F, CRANE 3,611,567

CENTRIFUGAL DRIVE FOR ELECTRIC RAZOR Filed April 14, 1969 22 vie mvewrora.

5E2 ream E Gen/a5 ATTO RN EV United States 1;;

Patented Oct. 12, 1971 US. Cl. 30-413 9 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein is an electric shaver having a shaving head comprising an outer or female member having a polygonal bore defining an internal bearing surface, a number of segments defining cutting elements adjustably mounted on the outer member symmetrically with respect to the bore, an inner or male member supported on the outer member and having a peripheral polygonal bearing surface positioned within said bore and a cutting edge positioned to operatively engage the cutting elements of the segments, an electric motor and a variable radius eccentric drive assembly operatively connected to the mtor and to the inner member to provide a polygonal tracing movement of the inner member relative to the outer member. A sharpening device is also included and is adapted to be mounted on the inner member to sharpen the segments or on the segments to sharpen the inner member.

BACKGROUND OF THE INVENTION Electric shavers having interacting polygonal cutting edges are disclosed in my Pat. No. 3,344,517, issued Oct. 3, 1967.

SUMMARY OF THE INVENTION The electric shaver of this invention is provided with a variable radius eccentric drive assembly to produce cyclic movement of an inner member having a polygonal cutting edge with respect to an outer member having a number of segments forming a polygonal cutting element. The outer member has an internal polygonal bore defining the trace or path of motion of the inner member. The segments are mounted on the outer member symmetrically with respect to the polygonal bore to define a polygonal cutting element. A nipping and slicing action is produced between the cutting edges and cutting elements by the tracing movement of the inner member about the polygonal bore of the outer member. The segments are adjustable to vary the spacing between the cutting edges of the inner member and the cutting elements to minimize wear. Vibration of the shaver is substantially eliminated by providing a counterweight in the drive assembly to counterbalance the movement of the eccentric drive.

The shaver is sharpened while operating by a novel sharpening device which comprises a hone having a flat planar surface that is held against the adjustable segments to hone the inner member and attached to the inner member to hone the segments.

Other objects and advantages of the invention will become apparent from the following detailed description when read in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of the shaver of this invention.

FIG. 2 is an exploded view of the shaving head and drive assembly.

FIG. 3 is a top view of the shaving head.

FIG. 4 is a section view of the shaving head taken on line 44 of FIG. 3.

FIG. 5 is a section view showing the drive connection between the motor and the shaver head.

FIG. 6 is a view in section of a portion of a modified type of adjustable segment having an annular cutting edge.

DESCRIPTION OF THE INVENTION Referring to FIG. 1 of the drawing, the electric shaver of this invention generally includes a shaving head 10 mounted on a casing 12 for a drive assembly 14. Power for the drive assembly 14 is provided by a suitable motor positioned within a housing 16 secured to the casing 12 with the drive shaft 18 of the motor extending through an aperture 20 into a central cavity 22 in the casing 12.

The shaving head 10 includes a first, outer or female member 24 and a second, inner or male member 26. Means are provided on the outer member for defining a series of inwardly directed cutting elements 30 in the form of a number of cutting segments 28 adjustably mounted on the onter member 24. The inner member 26 has peripheral cutting edges 32 and is supported on the outer member 24 for relative movement with respect to the segments 28 to produce a nipping and slicing action between the cutting edges 32 and the cutting elements 30.

The outer member 24 is in the form of a cylinder 34 closed at one end by a wall 36 having an inner planar surface 38 and an outer planar surface 40. The inner and outer surfaces 38 and 40 of the Wall 36 are parallel to each other and perpendicular to the longitudinal axis of the cylinder 34 to provide accurate bearing surfaces for the inner member 26 as described below. Means are provided in the wall 36 to define a bearing surface of polygonal configuration in the form of an internal bore 42 having a number of flat bearing surfaces 44. While the polygonal bore 42 may have any number of bearing surfaces 44, in the preferred embodiment, a triangular configuration is shown.

The cutting segments 28 can take any form and include a flat inner wall 48, a face portion and a support surface 52. The face portion 50 and support surface 52 are parallel to each other and perpendicular to the inner wall 48. The cutting element 30 of FIG. 2 is formed on the inner wall 48 by means of a flange 54 which forms a continuation of the face portion 50 and terminates at a flat cutting surface 46. A pair of elliptical mounting holes 56 are provided in each of the segments 28. The longitudinal axes of the mounting holes 56 are parallel to each other and perpendicular to the inner wall 48.

In FIG. 6, a modified type segment 29 is shown having a cutting element 30 formed on the inner wall by means of a flange 53 having an upwardly inclined surface glich intersects the face portion SID to define cutting edge Means are provided for adjustably mounting the cutting segments 28 on the upper surface 40 of the outer member 24 in the form of a number of flat head screws 58 which extend through the elliptical openings 56 and are threadedly received in threaded openings 60 provided in the wall 36. The cutting elements 30* on the cutting segments 28 are positioned in a parallel relation to the bearing surfaces 44 and in a perpendicular relation to a radial line drawn through the axis of the cylinder 34. The segments 28 are moved radially to adjust the spacing between the cutting elements 30 and cutting edges 32 and the screws 58 tightened to hold the segments in position.

The inner member 26 includes a polygonal shaped head 62 and a depending cylindrical shank or rod 64. The head 62 has a flat upper surface 66 which terminates at the peripheral polygonal cutting edge 32 formed by the intersection of upwardly inclined Walls 68 and the flat upper surface 66. A number of peripheral bearing surfaces 70 are provided around the periphery of the head 62 corresponding in number to the number of bearing surfaces 44 provided in the polygonal bore 42. The cutting edges 3 32 correspond in number and are symmetrical with respect to the bearing surfaces 70.

The inner member 26 is mounted on the outer member 24 with the peripheral bearing surfaces 70' positioned within the polygonal bore 42 and is supported for sliding movement on the upper surface 40 of the outer member 24 by means of a flat bearing surface 72. In this regard, the bearing surface 72 is perpendicular to the axis of the inner member 26 and is free to slide on the upper surface 40 of the outer member 24.

A flat coplanar surface to engage the skin of the shaver is formed by means of the upper surface 66 of the inner member 26 and the face portions '50 of the segments 28. In this regard, the bearing surface 72 is spaced from the upper surface 66 of the inner member 26 a distance equal to the distance between the face portion 50- of the segment 28 from the support surface '52 of the segment 28. The upper surface 66 and face portion 50 of the guide segments 28 then form a flat coplanar surface for engagement with the skin.

In order to retain the inner member 26 on the outer member 24, means are provided within the cylinder 34 to fixedly engage the shank 64 and to bear against the inner surface 38 of the wall 36. Such retaining means is in the form of a retaining disc 74 having a central aperture 76 to receive the shank 64 and a set screw 78 threadedly received in a threaded bore 80 in the sidewall of the disc in a position to engage the shank 64. The upper surface 82 of the disc 74 acts as a bearing surface and is positioned in abutting engagement with the inner surface 38 of the wall 36. An opening 84 is provided in the cylinder 34 to aid in tightening the set screw 7 8.

Various means can be used to secure the shaving head to the casing 12. Such means being shown in the form of a number of screws 86 which are arranged in the casing 12 in a position to engage a number of corresponding openings 88 in the cylinder 34. More specifically, the easing 12 includes an annular groove 90 having an outside diameter slightly larger than the outside diameter of the cylinder 34. The lower edge of the cylinder 34 is positioned in the groove 90 and is retained therein by the screws 86 which engage the corresponding openings 88 in the cylinder 34.

In order to produce a nipping and slicing action between the cutting edge 32 and the cutting element 30, the inner member 26 is moved relative to the outer member 24 by means of the drive assembly 14 which is housed in the central cavity 22 of the casing 12. The drive assembly 14 includes a drive disc 92 having a lower surface 91 and a cylindrical extension or stud 96 depending axially from the lower surface. The disc 92 also has an upper surface 93 parallel to the lower surface 91 and is provided with a centrally located cavity 94 to receive the shank 64 of the inner member 26. The cavity 94 has a diameter larger than the diameter of the shank 64 so that the disc will not interfere with the movement of the inner member 26. The disc 92 is driven off of the drive shaft 18 of the motor by means of a gear 104 secured to the end of the stud 96 by a key 106 and a worm gear 108 provided on the motor drive shaft 18. Although a worm gear has been shown in the drawing, any other type drive could be used which will produce the necessary speed.

The drive assembly also includes a guide block 98 having an axially extending bore 100' to receive the stud 96. Friction between the drive disc 92 and the guide block 98 is reduced to a minimum by means of a bearing flange 102 provided around the periphery of the bore 100 m a position to engage a portion of the lower surface 91 of disc 92.

The rotary motion of the disc 92 is converted to a tracing movement of the inner member 26 around the polygonal bore 42 of the outer member 24 by means of a loose member or sector 110 journalled on the shank 64 of the inner member 26 and positioned between the retaining disc 74 and the drive disc 92. The sector 110 is provided with a sleeve bearing 112 having an internal bore 114 to receive the shank 64 and an annular bearing flange 115 to reduce the surface area of contact between the sector 110 and the retaining disc 74. The sector 110 is placed on the upper surface 93 of the drive disc 92 and is free to move radially relative to the upper surface 93 of the drive disc 92. The rotary motion of the drive disc 92 can be imparted to the sector 110 by various means such as pins 116 provided on the drive disc 92 in a position to engage the edges of the sector 110.

The nipping and slicing action is produced by means of the variation in the radius of rotation of the geometric center of the sector 110 as it is rotated around the shank 64. In this regard the sector 110 is free to move radially on the drive disc 92 and the centrifugal force set up in response to rotation of the sector 110 Will pull the inner member 26 into engagement with the bearing surfaces 44 in the outer member 24. The inner member 26 will move along one of the bearing surfaces 44 toward the next bearing surface 44. The outer limit of radial movement of the sector 110 being defined by the internal bearing surfaces 44. When the inner member 26 is moved into engagement with one of the bearing surfaces 44, a nipping action will be produced between the cutting edge 32 and the cutting element 30. When the inner member 26 moves relative to the engaged bearing surface 44, a slicing action will be produced between the cutting edge 32 and the cutting element 30.

The variation in radius of the geometric center of the sector 110 to produce the nipping and slicing action can be seen in FIG. 3 where a radial line 120 is shown drawn from the axis 122 of the cylinder 34 out to the apex of two of the polygonal cutting elements 30. As the radial line 120 is rotated, counterclockwise, the outer end of the radial line 120 will follow the line of the cutting element 30 and will become shorter as it approaches the midpoint of cutting element 30. The radial line 120 will become longer as it approaches the apex formed by the next cutting element 30. The distance of the geometric center of the sector 110 will follow substantially the same path of motion although on a much smaller scale since the sector 110 and inner member 26 follow the trace of the bearing surfaces 44 in the bore 42. The inner member 26 and sector 110 will move radially outwardly toward the apex of two adjacent bearing surfaces 44 and radially inwardly from the apex to the midpoint of the bearing surface 44 in the direction of rotation. After the geometric center of the sector 110 passes the midpoint of the bearing surface 44, the centrifugal force acting on the sector 110 displaces the inner member 26 toward the next bearing surface 44 and produces the nipping and slicing action. I

Vibration of the shaving head 10 is substantially eliminated by means of a counterweight secured to the surface of the disc 92 in the same plane as the eccentric sector 110 and having substantially the same weight as the sector. Although the geometric center of the sector 110 will vary due to its freedom of movement on the surface of the disc 92, error is quite small in view of the small amount of motion involved in the movement of the sector on the surface of the disc 92.

In the preferred embodiment of the invention, the polygonal bearing surfaces 44 are arranged in an equilateral triangle with the cutting edges 32 on the inner member 26 about an inch in length. The maximum perpendicular distance of separation between the cutting edge 32 and the cutting elements 30 is about .025 inch. In the case of equilateral triangles, if the inner member 26 is symmetrical with respect to the cutting element 30', the spacing becomes one-third thereof or about .008 inch. The radial change or deviation to make contact therefor varies from .008 to .016 inch. On the other hand, the radius of the eccentric sector 110 is .569 inch. The radius of the mass for .569 inch would be about .402 inch.

The ratio of radial change to radial length of the mass centroid is about DOS/.402 or parts in a thousand. Consequently, a counterweight offsetting the average centrifugal force with an error of only 5 parts in a thousand will substantially eliminate vibration in the shaving head 10.

Means are provided for sharpening the shaver in the form of a hone 140 having a central aperture 142 and a pin 1-44. A bore 146 is provided in the inner member 26 to receive the pin 140. The hone 140 is held against the segments 28 while the shaver is operating to hone the face 66 of the inner member 26. The face portions 50 of the segments 28 are honed by inserting the pin 144', into the aperture 142 in the hone 14d and the bore 146 in the inner member 26. The hone 140 is then held against the face portions 50 of the segments 28 while the inner member 26 is operating to displace the hone relative to the face portions 50.

I claim:

1. An electric shaver comprising a first member having means defining an internal bore having a bearing surface of polygonal configuration, means mounted on said first member for defining a series of internal cutting elements of polygonal configuration symmetrical to said internal bore, a second member carried by said first member and having a peripheral bearing surface of polygonal configuration corresponding to and cooperable with said internal bearing surface and external cutting edges of polygonal configuration corresponding to and cooperable with said internal cutting elements, an electric motor, and means for operatively connecting said electric motor to one of said first and second members for moving said first and second members relative to each other to produce a nipping and slicing motion between said cutting edges and said cutting elements, said connecting means including a sector rotatably driven by said electric motor and urged radially outwardly in response to rotation.

2. An electric shaver according to claim ll wherein said sector is journalled on said second member and wherein rotation of said sector produces a tracing movement of said second member about said internal bearing surface, said internal bearing surface defining the outermost limit of radial movement of said sector.

3. An electric shaver according to claim ll wherein said means for defining said cutting elements is adjustably mounted on said first member.

4. An electric shaver according to claim ll wherein said means for defining said cutting elements comprises a number of segments adjustably mounted on said first member.

5. An electric shaver according to claim 4 wherein each of said segments includes a face portion and said cutting element is defined by a fiat surface perpendicular to said face portion.

6. An electric shaver according to claim 4 wherein each of said segments includes a face portion and said cutting element is defined by a surface angularly disposed to said face portion.

7. An electric shaver according to claim 1 wherein said means for defining a bore includes a face portion and said second member includes a flat upper portion coplanar with said face portion.

8. An electric shaver according to claim 1 wherein said connecting means further includes a drive disc driven by said motor and a counterweight secured to said drive disc in a position diametrically opposite to said sector.

9. A shaving head comprising a femal member having a fiat surface with a triangular bore defining a number of bearing surfaces, a number of segments corresponding in number to the number of bearing surfaces, said segments being secured to said flat surface, each segment including a face portion adapted to engage the skin of a shaver and a cutting element, a male member supported by said female member and including a triangular peripheral bearing surface positioned within said triangular bore, said male member including a flat surface coplanar with said face portion of said segments and a peripheral cutting edge, means for retaining said male member on said female member and means for moving said male member with respect to said female member in a triangular tracing movement defined by said triangular bore and said peripheral bearing surfaces to provide a nipping and slicing cutting action between said cutting edges and said cutting elements, said moving means including a sector journalled on said male member and urged radially outwardly in response to rotation, the outward limit of radial movement being defined by said triangular bore.

References @ited UNITED STATES PATENTS 1,918,625 7/1933 \Vills -41.9 2,272,053 2/1942 Altemus 304l.9 X 3,344,517 10/1967 Crane 30-4l.9

ROBERT C. RIORDON, Primary Examiner U.S. Cl. X.R. 3043.3, 181 

